Developer · JSON Web Tokens
JWT expiry calculator.
Paste a token to see whether it has expired, how long it has left and how long it lived. The token is decoded in this page and is never sent anywhere.
Check a token
Result
Paste a token, a timestamp or a duration and press Calculate.
How JWT expiry works
RFC 7519 defines three time claims as NumericDate values, seconds since 1970-01-01T00:00:00Z: exp (expiration), nbf (not before) and iat (issued at). A token must not be accepted on or after its exp time and must not be accepted before nbf.
Lifetime is exp - iat. To issue a token that lasts an hour, set exp to the current epoch seconds plus 3600. If a value has 13 digits it is probably milliseconds, which JWT does not use.
Source: IETF RFC 7519, sections 2 and 4.1.4 to 4.1.6. This page decodes the payload only; verifying a signature needs the issuer’s key and belongs in your server.
Frequently asked questions
Is my token sent to a server?
No. The token is decoded in this page with built-in browser functions. The page also loads no advertising or analytics scripts.
Does this verify the signature?
No. It reads the claims only, so an unexpired result is not proof the token is genuine.
Why does my token say expired when the server accepts it?
Servers may allow clock skew. This page compares against your device clock with no leeway.
Handle tokens with care
Do not paste production tokens that are still valid into any online tool you do not trust. Expire or rotate a token you have shared.